In 1931 he became European champion in the lightweight division and in 1938 he won the same title in the middleweight division. During his professional tenure, van Klaveren was able to achieve victories over Ceferino Garcia and Kid Azteca. He also faced Hall of Famers Young Corbett III and Billy Petrolle in defeat. Van Klaveren contested his last match at age 48, on 19 March 1956. His younger brother Piet competed as a boxer for The Netherlands at the 1952 Summer Olympics.

In 1992, a memorial statue was dedicated for van Klaveren in Rotterdam, which was designed by Dutch sculptor Willem Verbon. To this day, van Klaveren remains the only Dutchman to have ever won an Olympic Gold Medal in boxing.